Abstract

A series of experiments have shown that the elastic wave velocities and attenuation are dependent on frequency (Jones, 1986; Sams et al., 1997; Batzle et al., 2006). Velocity dispersion and attenuation may make it difficult to match different frequency bands of geophysical data such as surface seismic and VSP (∼5 to 300 Hz), sonic log (1 kHz to 20 kHz), and ultrasonic core survey (>105 Hz). For example, sonic log data are often used to constrain seismic inversion on the assumption that log velocity equals to seismic velocity at well locations. However, these two sets of velocities are different due to the effect of velocity dispersion, especially in reservoirs. Therefore, if we could develop a proper frequency-dependent rock physics model to correct the data at the sonic frequency band to that at the seismic frequency band, it would be useful for the solution to the data-matching problem.